The specific aim of this research proposal is to investigate morbidity and mortality associated with the fine and coarse fractions of PM10 particulate air pollution, and of ambient carbon monoxide in Anchorage, Alaska, where the coarse fraction of PM10 is the dominant fraction. The proposal consists of three projects. 1. Investigate the association between daily outpatient visits and changes in PM10, PM2.5, and ambient CO adjusted for meteorologic conditions. 2. Quantify the temporal association between hospital admissions for respiratory or cardiovascular illness and daily measurements Of PM10, PM2.5, and ambient CO adjusted for meteorologic conditions. 3. Quantify the associations between daily mortality and daily PM10 pollution for the 10-year period 1986-1996 using mortality records. Epidemiologic studies to date have shown significant associations with ambient PM10 concentrations and acute health endpoints measured either in terms of daily mortality, hospital admissions or emergency room visits. Because of lack of historic fine particle (PM2.5) or coarse particle (PM2.5-10) measurements, these studies could not directly test which component of PM10 contributes most to the inferred health effects relationships. Dicot measurements Of PM2.5/PM10 taken during the last two years at the same site in Anchorage, Alaska, showed a high correlation of PM10 with the coarse fraction, while PM2.5 has a low correlation with PM10. The consistency of the magnitude of the effect of particulate concentration on mortality and morbidity is striking considering the variations in the physico-chemical properties of particulates across studies reported. An Anchorage study done in 1995 by the same researchers showed that Anchorage PM10 had morbidity effects similar to what has been shown in other areas. This study will look at both outpatient visits for a healthy working population, hospital admissions, and mortality. Because the specific fraction of the PM10 that causes health effects is a major concern, the proposed study will address key issues facing EPA, DOE and industry during the ongoing revision of the PM10 standard.